Digital Subscriber Line signal architectures, generally denoted as xDSL, allow digital distribution of combined broadband video and data services with traditional narrowband voice transmissions.
One form of xDSL of particular interest to the present invention is VDSL (Very high speed Digital Subscriber Line), which is a packet-based transmission architecture used to provide extremely high bandwidth distribution of digital video and data signals to subscribers. A VDSL-based architecture can advantageously provide a single platform for supporting bandwidth-intensive applications, such as Internet access, remote LAN access, video conferencing, and video-on-demand.
ADSL or Asymmetric Digital Subscriber Line services generally use existing unshielded twisted pair (UTP) copper wires from a telephone company's central office to the subscriber's premise, utilize electronic equipment in the form of ADSL modems at both the central office and the subscriber's premise, send high-speed digital signals up and down those copper wires, and send more information one way than the other. The ADSL type of xDSL services is capable of providing a downstream bandwidth of approximately 1.5 Mbps-8 Mbps, and upstream bandwidth of about 16 Kbps-64 Kbps with loop distances ranging from about 3.7 km-5.5 km. HDSL or High bit rate Digital Subscriber Line services provide a symmetric, high performance connection over a shorter loop, and typically require two or three copper twisted pairs. HDSL is capable of providing both upstream and downstream bandwidth of approximately 1.5 Mbps, over loop distances of up to approximately 3.7 km. SDSL or single line digital services provide a symmetric connection that matches HDSL performance using a single twisted pair, but operating over a shorter loop of up to approximately 3.0 km.
VDSL services are typically implemented in an asymmetric form having a downstream transmission capability of approximately 52 Mbps over twisted pair copper wire arranged in local loops of 300 m, 26 Mbps at 1,000 m, and 13 Mbps at 1,500 m. Upstream data rates in asymmetric implementations tend to range from approximately 1.6 Mbps to approximately 2.3 Mbps. As though skill in the art will recognize, a typical distribution system includes a central office equipped with a Host Digital Terminal (HDT) and arranged to operate as a hub between multiple Video Information Providers (VIPs)/Digital Service Providers (DSPs) and customer residential dwellings. In a Fiber-To-The-Neighborhood (FTTN) type distribution system, optic fiber (e.g. OC-3 c and OC-12 c) lines are used to connect the central office to a Universal System Access Multiplexer (USAM), which is then connected to a Network Interface Device (NID) located on the customer property via twisted pair copper wire. A dedicated VDSL loop extends between the NID and an individual customer residence using an existing POTS or telephone system twisted pair wire, and a customer interface device, such as a residential gateway or set top box, provides a connection point for a customer display device such as a television or personal computer. A Fiber-To-The-Curb (FTTC) type distribution system is similar except that a Broadband Network Unit (BNU) is used in place of the USAM, and coaxial cable is used to connect the BNU, NID, and set top box.
The VDSL signal format is used to carry signals to and from the customer. In these systems, the central office provisions each user for programming access rights, and maintains a profile database for each provisioned customer at the HDT to control the signals/channels that can be viewed by the customer.
As readily seen, broadband broadcast networks, and in particular, VDSL networks are complex communication systems. To insure proper operation, it is desirable to verify the VDSL signals and, as appropriate, isolate and resolve logical layer (layer 2-ATM) connectivity end-to-end. That is, from the customer side xDSL modem to a serving Internet Services Provider (ISP). Presently, however, no known system or method provides this functionality. Without this mechanism, trouble isolation and restoration is time-consuming and customer inconvenient as each component of the xDSL network must be individually identified and tested and the resultant data collected, analyzed, and compared to locate a logical layer fault. The test system uses current switching ATM layer and physical layer diagnostic capabilities. The method combines a rules system for providing an aggregated view of topology.